Environmental Engineering Reference
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The initial task was to verify the feasibility of converting the above mentioned
residues into pellets.
2.4 Results and Discussion
The results presented in this paper are part of an extensive research process, ana-
lyzing the viability of pelleting Brazilian biomass. Since some experiments are
still in process, we described the preliminary properties of the residues. The water
content analysis of the studied biomass was used to determine the processing fea-
sibility of the material. After the harvest, the biomass moisture varied from 14 to
16%. Such high moisture content can cause the decomposition of the material and
increase the transport costs. Hence, reducing the water content of the biomass was
a necessary step before pelleting. In Brazil, drying the residues was done with
minimum costs, due to the availability of space and workforce. However, process-
ing biomass with high moisture could be a time, energy and money consuming ac-
tivity. The biomass was exposed to air and constantly revolved for approximately
six weeks during the dry season. The material could be then transported with a
moisture value of maximum 13%.
Figure 2.2
shows the moisture content for dif-
ferent types of residues. Coffee husks and saw wood had satisfactory moisture
values after the drying period. Sugar cane bagasse presented the lowest value de-
spite its high juice content. Considering that bagasse and rice husks presented
moisture content varying from 7 and 9% respectively, this biomass would need a
shorter drying period.
Fig. 2.2.
Moisture content for different types of residues
The percentage of ash formed by the combustion process related to the total water
free weight of the used material and is a relevant parameter for determining the
pellet mixtures. As shown in
Figure 2.3
, rice husks presented high ash content.
This hinders the economic feasibility of the fuel, due to the high costs of removing
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